Part A.Answer all eight questions(5 marks each). 1.Use VSEPR theory to predict the shape of the NF3 ion. 5+(3x7)+1 =27 electrons.Making single bonds,completing the octets around the F atoms uses 24 electrons The other three are placed as a lone pair plus a single electron on the N atom.The molecule is therefore of the form AX3E2.The shape is therefore T-shaped 2.For the reaction C+CO=2 CO which direction(left or right)will the equilibrium shift if the pressure is decreased?Why? The reaction will shift to the right in order to increase the pressure,according to le Chatelier's principle 3.Which of HCIO and HCIO2 is the stronger acid?Why? HCIO2 is the stronger acid.The extra Oatom draws electrons towards itself,withdrawing electrons from the O- H bond,weakening it and making it a stronger acid. 4.Name three ways to prevent or slow the corrosion of an object made of iron metal. 1.Paint it to prevent contact with oxygen and water. 2.Use passive cathodic protection. 3.Use active cathodic protection. 5.Define the term"state function"and give three examples of one A state function is one whose value does not depend on the path taken from reactants to products,nor on the rate.Three examples are H,S and G. Part B.Answer all four questions(20 marks each). 1. Calculate the lattice energy (in kJ mol)of CaO from the following data: (i)The bond energy of the O2 molecule is +495.0 kJ mol"Part A. Answer all eight questions (5 marks each). 1. Use VSEPR theory to predict the shape of the NF3 ¯ ion. 5 + (3x7) + 1 = 27 electrons. Making single bonds, completing the octets around the F atoms uses 24 electrons. The other three are placed as a lone pair plus a single electron on the N atom. The molecule is therefore of the form AX3E2. The shape is therefore T-shaped 2. For the reaction C(s) + CO2(g) = 2 CO(g), which direction (left or right) will the equilibrium shift if the pressure is decreased? Why? The reaction will shift to the right in order to increase the pressure, according to le Chatelier’s principle. 3. Which of HClO and HClO2 is the stronger acid? Why? HClO2 is the stronger acid. The extra O atom draws electrons towards itself, withdrawing electrons from the O￾H bond, weakening it and making it a stronger acid. 4. Name three ways to prevent or slow the corrosion of an object made of iron metal. 1. Paint it to prevent contact with oxygen and water. 2. Use passive cathodic protection. 3. Use active cathodic protection. 5. Define the term “state function” and give three examples of one. A state function is one whose value does not depend on the path taken from reactants to products, nor on the rate. Three examples are H, S and G. Part B. Answer all four questions (20 marks each). 1. Calculate the lattice energy (in kJ mol-1) of CaO(s) from the following data: (i) The bond energy of the O2(g) molecule is +495.0 kJ mol-1